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Toxicological information

Developmental toxicity / teratogenicity

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Administrative data

Endpoint:
developmental toxicity
Type of information:
experimental study
Adequacy of study:
key study
Study period:
January 29, 2008 to September 13, 2008 (experimental period)
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline study, well performed and reported according to good scientific standards

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2009
Report Date:
2009

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 414 (Prenatal Developmental Toxicity Study)
Deviations:
no
Qualifier:
according to
Guideline:
EPA OPPTS 870.3700 (Prenatal Developmental Toxicity Study)
Deviations:
no
Qualifier:
according to
Guideline:
other: Japanese MAFF, 12 Nohsan No. 8147, Teratology (2-1-18) (November 2000)
Deviations:
no
GLP compliance:
yes
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): TPI 1618
- Substance type: Formaldehyde releaser
- Physical state: Clear liquid; density: 1.254 g/mL
- Analytical purity: Splittable formaldehyde: 46% (range 42.3 – 51.7%);
- Composition of test material, percentage of components: Reaction product of ethylene glycol, urea and paraformaldehyde (EUF)
- Purity test date: Nov 2007
- Lot/batch No.: 1129290
- Expiration date of the lot/batch: August 2010
- Stability under test conditions: stable under test condition
- Storage condition of test material: at room temperature

Test animals

Species:
rabbit
Strain:
Himalayan
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River, Germany
- Age at study initiation: 31 to 45 weeks
- Weight at study initiation: 2.282 to 3.498 kg at study start
- Fasting period before study: no
- Housing: Individually in stainless steel cages
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: 7 days under test conditions with health check

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18+-3
- Humidity (%): 30-70
- Air changes (per hr): 10-15
- Photoperiod (12 hrs dark / 12 hrs light):

IN-LIFE DATES: From 22 January 2008 to 13 March 2008:

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
other: Milli-Q-Water
Details on exposure:
PREPARATION OF DOSING SOLUTIONS:
Prepared daily as supplied by Sponsor and diluted with Milli-Q-Water

VEHICLE
- Justification for use and choice of vehicle (if other than water): Milli-Q-Water (highly purified water) was used to avoid interference with the analytical controls of dosing solutions
- Concentration in vehicle: 13.75, 27.5 and 55%
- Amount of vehicle (if gavage): 4 mL/kg bw
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
On the first day and last week of treatment, samples from control and all 3 dose levels were taken for analysis of concentration and homogeneity and analysed by GC.
Details on mating procedure:
- Impregnation procedure: cohoused
- If cohoused: in individual cages
- M/F ratio per cage: 1/1
- Length of cohabitation: until successful copulation was observed
- Further matings after two unsuccessful attempts: not applicable, only proven males from supplier were used
- Verification of same strain and source of both sexes: yes
- Proof of pregnancy: day of mating referred to as day 0 of pregnancy
Duration of treatment / exposure:
Treatment was performed from Day 6 to 27 post coitum
Frequency of treatment:
Once daily
Duration of test:
28 days
No. of animals per sex per dose:
20 mated females per group
Control animals:
yes, concurrent vehicle
Details on study design:
- Dose selection rationale: Dose levels were selected after a preliminary dose range finding with dose levels of 60, 120 and 240 mg/kg bw/day, resulting in a NOAEL of 120 mg/kg bw/day

Examinations

Maternal examinations:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: once daily

DETAILED CLINICAL OBSERVATIONS: No

BODY WEIGHT: Yes
- Time schedule for examinations: Recorded daily from day 0 until day 28 post coitum
Summarised for the following periods: days 0-3, 3-6, 6-9, 9-12, 12-15, 15-18, 18-21, 21-24 and 24-28 post coitum

FOOD CONSUMPTION: Yes
- Food consumption for each animal determined and mean daily diet consumption calculated: Yes

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day 28
- Organs examined: all internal organs with emphasis on uterus and contents

Ovaries and uterine content:
The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: Yes
- Number of corpora lutea: Yes
- Number of implantations: Yes
- Number of early resorptions: Yes
- Number of late resorptions: Yes
Fetal examinations:
- External examinations: Yes: all per litter
- Soft tissue examinations: Yes: all per litter
- Skeletal examinations: Yes: all per litter
- Head examinations: Yes: half per litter
Statistics:
Dunnet test (if variables followed a normal distribution)
Steel test (if variables did not follow a normal distribution)
Fisher's exact test (for macroscopic data evaluation)
Indices:
Pre-implanatation loss
Post-implantation loss
Historical control data:
Yes

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:
Maternal toxic effects:yes

Details on maternal toxic effects:
Maternal toxicity was present from 110 mg/kg bw (group 3) onwards. Beginning at this dose level, mean food consumption and mean body weight gains were transiently reduced after the beginning of treatment. During necropsy for one female a red area in the pylorus region in the stomach was noted (most likely as sign of formaldehyde-induced local irritation).

At 220 mg/kg/day, five females were found dead or killed for ethical reasons. They showed a genital region smeared with urine and/or feces, ventral recumbence or reduced activity and ruffled fur. Mean food consumption and mean body weights were reduced during the treatment period. The mean post-implantation loss was statistically significantly increased, resulting in a statistically significantly reduced number of fetuses. During necropsy, several females showed a stomach with crateriform areas, ulcerations or reddish discolorations

Effect levels (maternal animals)

Dose descriptor:
NOAEL
Effect level:
>= 55 mg/kg bw/day (nominal)
Based on:
test mat.
Basis for effect level:
other: maternal toxicity

Results (fetuses)

Details on embryotoxic / teratogenic effects:
Embryotoxic / teratogenic effects:yes

Details on embryotoxic / teratogenic effects:
At the high dose (220 mg/kg bw), fetal parameters indicated that mean fetal body weights were statistically significantly reduced. Furthermore, a statistically significantly higher incidence of supernumerary ribs was noted. Post-implantation loss was increased.

Effect levels (fetuses)

Dose descriptor:
NOAEL
Effect level:
>= 110 mg/kg bw/day
Based on:
test mat.
Basis for effect level:
other: fetotoxicity

Fetal abnormalities

Abnormalities:
not specified

Overall developmental toxicity

Developmental effects observed:
not specified

Any other information on results incl. tables

Tables for maternal and fetal effects see under attached documents

Applicant's summary and conclusion

Conclusions:
EUF (TPI 1618) administered orally during the major phase of organogenesis to pregnant Himalayan rabbits resulted in no indication for teratogenicity, but influenced fetal development at a moderate to severe maternal toxic dose. The NO(A)EL for maternal toxicity was 55 mg/kg bw and the NO(A)EL for fetal development was 110 mg/kg bw/day.
Executive summary:

The present study was designed to evaluate the potential of EUF (TPI 1618) to produce maternal and developmental toxicty (including teratogenicity) when administered by oral gavage during major organogenesis and fetal development in the Himalayan rabbit. The investigation was compliant with OECD 414 (2001), US-EPA OPPTS 870.3700 (1998) and Japanese MAFF (2000).
Dose levels of 55 (group 2), 110 (group 3) and 220 (group 4) mg/kg bw were given once daily from Day 6 to 27 p.c. to 20 mated rabbits per group.

The NO(A)EL for maternal toxicity was 55 mg/kg bw and the NO(A)EL for fetal development was 110 mg/kg bw/day.